1	First flagellomere slightly produced anterodistally, forming an angle (Fig. 95). Mid tibia with one posteromedial seta that is sometimes reduced to absent. Hypophallus divided into two J-shaped lateral bands, each 1/2 having a short basomedial curve (Figs 468–470)	2
–	First flagellomere circular (Fig. 96); if with a slight angle (some C.promissa), then with two mid tibial setae. Mid tibia usually with two or three posteromedial setae (one or more setae reduced in C.platyptera and some C.promissa). Hypophallus without medial curve as above	3
2	Face entirely brown (Fig. 94). Wing length 1.4–1.6 mm ♂, 1.6–2.0 mm ♀. Small medial sclerite between mesophallus and distiphallus absent (Fig. 468). Halves of distiphallus dark, closely spaced; each tubule (seen laterally) relatively narrow and opening distally	C.humeralis (Roser)
–	Face yellow, sometimes with brown region below antennal bases. Wing length 1.6–2.0 mm ♂, 2.0–2.3 mm ♀. Small medial sclerite between mesophallus and distiphallus present (Fig. 470). Halves of distiphallus relatively pale, widely spaced; each tubule (seen laterally) relatively broad with opening angled dorsally	C.solidaginis (Kaltenbach)
3	Five or six pairs of fronto-orbital setae. Wing length 2.9–3.2 mm	4
–	Four pairs of fronto-orbitals; additional ori sometimes present only on one side in larger specimens. Wing length 1.5–2.7 mm	5
4	Scutum with one pair of large yellow posterolateral spots overlapping margin of scutellum (Fig. 98). Fronto-orbital plate entirely yellow. Face, scape, pedicel, lower margin of gena and apex of fore femur yellow. Two well-developed posterior dorsocentral setae and one smaller anterior dorsocentral. Distiphallus widest at basal cup-like structure; fringed inner structures projecting (Fig. 459)	C.flavinotum (Frick)
–	Scutum with smaller, faded yellowish posterolateral spots. Fronto-orbital plate brown in part, at least to base of posterior ors. Face, pedicel, scape, lower margin of gena and apex of fore femur brown. Six dorsocentral setae, steadily decreasing in size anteriorly. Distiphallus widest apically; fringed inner processes concealed (Fig. 465)	C.gigantea (Frick)
5	Calypter margin and hairs entirely pure white. Puparium elevated on a lump or distinct stalk of frass	6
–	Calypter margin yellow or dirty-white to brown (rarely white), with hairs golden to dark brown. Puparium not known to be elevated on frass stalk	7
6	Anterior (third) dorsocentral thin, < 1/2 length of mid dorsocentral; fourth dorsocentral never present. Posteromedial tibial setae sometimes variably reduced. Wing length 1.5–1.6 mm ♂ (up to 1.8 in Canadian specimens), 1.6–2.2 mm ♀. Hypophallus well-sclerotised on both sides and fused to basiphallus. Mesophallus slender with width ~ 1/3 length. Outer sheath on distiphallus dark and tapered (Figs 473, 474). Ejaculatory apodeme relatively clear and narrow (Fig. 472)	C.platyptera (Thompson)
–	Third dorsocentral nearly as thick as second dorsocentral and ~ 1/2–4/5 as long; small fourth sutural dorsocentral present. Mid tibia always with two posteromedial setae. Wing length 1.8–2.1 mm ♂, 2.3–2.6 mm ♀. Hypophallus membranous on left margin and separate from basiphallus. Mesophallus broad with width more than 1/2 length. Outer sheath on distiphallus relatively clear and flared (Figs 482, 483). Ejaculatory apodeme relatively dark, with width exceeding length (Fig. 480)	C.promissa (Frick)
7	Fronto-orbital plate dark at least to base of posterior ors, often continuing anteriorly as long distinct stripe or weak lateral stripe fading to base of anterior ors. Distiphallus bifid	8
–	Fronto-orbital plate at most with faint brownish stripe from posterior margin of frons to base of posterior ors along fronto-orbital plate. Distiphallus branched or undivided	9
8	Wing length 1.8–2.2 mm. Hypophallus membranous with lateral sclerotisation. Mesophallus stout, not much longer than wide. Halves of distiphallus subspherical, stout, with long membranous distolateral extension (Figs 476, 477)	C.malvae (Burgess)
–	Wing length 2.3–2.7 mm. Hypophallus large, plate-like. Mesophallus narrow, much longer than wide. Halves of distiphallus narrower, longer than wide (Figs 478, 479)	C.orientalis Spencer
9	Base of posterior ors surrounded by yellow. Paraphallus well-developed. Distiphallus composed of single tapered structure (Figs 461, 462). Mesophallus subcylindrical	C.frickiana Spencer
–	Frons with light brown stripe extending from posterior margin of frons to base of posterior ors along fronto-orbital plate. Paraphallus absent. Distiphallus not forming single, tapered sclerite as above. Mesophallus bulging near midpoint or base	10
10	Wing length 1.8–2.0 mm. Eye height divided by gena height: 3.4–3.6. Hypophallus large with medial triangular sclerotised section. Distiphallus narrow, subcylindrical and partially fused to mesophallus (Figs 454, 455). Mesophallus short and strongly constricted medially (seen ventrally)	C.barbarensis Spencer
–	Wing length 1.8–2.6 mm. Eye height divided by gena height: 3.8–5.4. Hypophallus narrower with centre membranous. Distiphallus broad, not cylindrical. Mesophallus long and not strongly constricted medially	11
11	Mesophallus not much longer than wide; small dark sclerite present between mesophallus and distiphallus; outer cover of distiphallus minutely spinulose internally, short, and exposing strongly produced and haired central structure (Figs 450, 451). Lateral margins of hypophallus membranous	C.avira Eiseman & Lonsdale
–	Mesophallus with length ~ 2 × width and bent ventrally at midpoint; dark sclerite between mesophallus and distiphallus absent; outer cover on distiphallus very dark, surrounding central haired structure (Figs 488, 489). Lateral margins of hypophallus well-sclerotised	C.verbenae (Hering)